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Should I replace them or just tighten the caps properly, maybe use some teflon tape? I ask because a tech i Know has been replacing service valves left and right, and I have just been tightening all the caps and replacing shrader cores. What do you guys do?

Depends where and how severe the leak is. If a new shrader and new cap (flare or o-ring) will prevent a leak, that sounds like the way to go. If on the other hand the brass part that goes up and down is leaking, sometimes its best to replace the entire valve. Many of the old units had a mechanical connection to the suction line and if that is leaking, a new valve may be in order. It really comes ddown to "what is the right thing to do".

Unfortunatley teflon will not hold up well to refrigerant. If they are king style valves that you need to crack to gain access with your gauges, it might be better to repair the valve. If on the other hand they are backseat valves that dont get opened often, then maybe sealing the brass cap will suffice. It wouldnt be a bad idea to note the leak and leave a note in the unit for other servicers to be sure caps are tight and not leaking.

Originally posted by filterchanger I have been able to stop all the leaks by just tightening the caps,in a real bad case I use teflon tape. I only use teflon on the main body caps not the service port caps.

Sounds like you're solving the problem....there's more than one way to stop a leak.Do you use your leak detector around the cap when you're done?

If everything was always done "by the book"....the book would never change.

Thanks for all your replies,yes i check to make sure there not leaking after and i can see why teflon shouldnt be used on the king valves. I just dont feel right charging a customer somewhere over 500 to stop a leak that I can stop by just tightening the caps. Ill just keep doing it the way I have been and let management bring it up, if they notice the tech is replacing valves about one set per day. Just dont seem like the right thing to do to the customer but Im not the management.